DE4332014A1 - Electrocoating lacquers and methods for lacquering electrically conductive substrates - Google Patents

Abstract

PCT No. PCT/EP94/03088 Sec. 371 Date Aug. 26, 1996 Sec. 102(e) Date Aug. 26, 1996 PCT Filed Sep. 15, 1994 PCT Pub. No. WO95/08597 PCT Pub. Date Mar. 30, 1995The invention relates to aqueous eletrocoating [sic] compositions containing cathodically depositable synthetic resins, which electrocoating compositions are characterized in that they contain polymer microparticles which have a particle size of 0.01 to 10 mu m and are preparable by reacting (a) a polyisocyanate or a mixture of polyisocyanates with (b) an organic compound containing not only at least one ethylenically unsaturated double bond but also at least one active hydrogen atom per molecule or a mixture of such organic compounds and (c) an organic compound containing not only at least one active hydrogen atom but also at least one tertiary amino group and/or at least one ketimine group and/or at least one aldimine group per molecule or a mixture of such organic compounds and, if desired, (d) an organic compound other than (b) and (c) containing at least one active hydrogen atom per molecule or a mixture of such organic compounds. The reaction product thus obtained is dispersed in water and subjected to free radical polymerization, with at least 5 percent of the tertiary and/or primary amino groups present in the reaction product being neutralized with a Br+E,uml o+EE nsted acid before, during or after dispersion.

Description

The invention relates to cathodic art Resin-containing aqueous electrodeposition paints and a Process for painting electrically conductive sub strate at which

• (1) the electrically conductive substrate in an aqueous immersed in electrocoating paint,
• (2) the substrate is switched as a cathode,
• (3) a film deposited on the substrate by direct current will be divorced,
• (4) the painted substrate from the electrodeposition paint is removed and
• (5) the deposited paint film is baked.

Electrically cathodic electrodepositable resins dross paints and the above-described cathodic Electrocoating in which the cathodic electrodepositable resins containing electrodepositable resins have been used for a long time and are known are used for the automatic painting of bulk goods,  in particular for automatic painting of driving tools, in particular automobile bodies in large Scope used (see for example Glasurit Handbook Paints and Paints, Curt R. Vincentz Verlag, Hannover, 1984, pages 374-384 and pages 457-462, as well as DE-A-35 18 732, DE-A-35 18 770, EP-A-40 090, EP-A-12 463, EP-A-259 181, EP-A-433 783 and EP-A-262,069).

In the coating of electrically conductive substrates with Help of the cathodic electrocoating process The problem arises that the edges of the paint the substrate only with an insufficiently thick paint layer to be painted. This has among others to Result that the edges of the painted substrate in the Compared to the surfaces of the painted substrate he high susceptibility to corrosion. Around to solve this problem is disclosed in EP-A-259 181 recommended, the electrocoat polymer microparticles to add a softening point that is at least 10 ° C above the bath temperature, a solubility parameter ter not exceeding 1.0 of the solubility spa parameter of the cathodic resin separates, a refractive index of 0.02-0.3 from Refractive index of the cathodic electrodepositable resin or a crosslink density of 0.01-5.05 mmol / g have to add. According to EP-A-433 783 should be the electrocoating polymer microparticles crosslinked urea-aldehyde, triazine-aldehyde or Phenol-aldehyde resins or polymer particles from untreated added to the (meth) acrylonitrile homo- or copolymers be set.

The addition of those disclosed in EP-A-259 181 and EP-A-433 783 described polymer microparticles to Elektrootauch Lacken leads in some cases to improve the  Edge coverage. Despite the improved edge coverage is the anticorrosion effect of the deposited Electrocoating films on the edge, however, insufficient. In addition, the addition of the in EP-A-259 181 and EP-A-433 783 described polymer microparticles after partly a reduction in the stability of the Electrocoating paint (occurrence of sedimentation in the Electrocoating), a deterioration of adhesion to the substrate and / or to overcoated lacquer layers, a strong deterioration of the course as well as a Reduction of the anti-corrosive effect of the abgeschie which results in electrocoat films.

The present invention underlying Aufga Benstellung consists in the provision of katho schisch separable synthetic resins containing aqueous Electrocoating, the paint films with respect to the State of the art provide improved properties. With the cathodic depositable art provided Resins containing aqueous electrodeposition paints in particular electrically conductive substrates with the help of the cathodic electrodeposition coating process can be obtained and paint films that are the Cover edges of the painted substrate well and little at least part of the above-described disadvantages of State of the art not or only in the diminished Show measure.

This task is surprisingly by the Provision of cathodically depositable synthetic resins containing, aqueous electrodeposition paints, the characterized in that they are polymer microparticles Chen with a particle size of 0.01 to 10 microns enthal which can be produced by

• (a) a polyisocyanate or a mixture of poly with isocyanates
• (b) an organic compound, per molecule both at least one ethylenically unsaturated Double bond as well as at least one active What contains hydrogen atom or a mixture of sol organic compounds and
• (c) an organic compound that is so per molecule probably at least one active hydrogen atom as also at least one tertiary amino group and / or at least one ketimine and / or at least one Aldimini group contains or a mixture of sol chen organic compounds and optionally
• (d) one of (b) and (c) different organic Compound containing at least one active molecule per molecule Contains hydrogen atom or a mixture of such organic compounds

is reacted in such a proportion that 3 to 80 percent of the NCO groups of component (a) with of component (b), 3 to 80 percent of the NCO groups component (a) with component (c) and 0 to 94 Percent of the NCO groups of component (a) with the Kom component (d) are reacted and the Um settlement product dispersed in water and free-radically is polymerized, wherein before, during or after the Dispersion at least 5 percent of the reaction product contained tertiary and / or primary amino groups are neutralized with a Brönsted acid.

The electrodeposition coatings according to the invention can be used as cathodically depositable resins in principle each one for aqueous electrocoating suitable aqueous cathodic  containable resin. The invention Electrocoating lacquers preferably contain cationic, amine-modified epoxy resins as a cathodic deposition bare synthetic resins.

Such synthetic resins are known and are described for example in DE-A-35 18 770, DE-A-35 18 732, EP-B-102 501, DE-A-27 01 002, US-A-4,104,147, EP-A-4090, EP-A-12,463, US-A-4,031,050, US-A-3,922,253, US-A-4,101,486, US-A-4,038,232 and US-A-4,017,438. In these patent documents is also the production of cationic, amine modifi grained epoxy resins described in detail.

Among cationic, amine-modified epoxy resins become cationic reaction products

• (α) optionally modified polyepoxides and
• (β) amines

Roger that. These cationic, amine-modified Epoxy resins can be prepared by reacting the components (α) and (β) and, if necessary, subsequent proto be made. But it is also possible an unmodified polyepoxide with an amine umzu and on the thus obtained amine-modified Epoxy resin to carry out further modifications.

By polyepoxides are meant compounds which contain two or more epoxide groups in the molecule.

Particularly preferred (α) components are compounds, which are produced by implementation of

• (i) a diepoxide compound or a mixture of diepoxide compounds having an epoxide equivalent weight under 2000 with  
• (ii) one under the given reaction conditions monofunctional towards epoxide groups containing a phenol or thiol group the compound or a mixture of such Links,

wherein components (i) and (ii) behave in one mole from 10: 1 to 1: 1, preferably 4: 1 to 1.5: 1, be used and the implementation of component (i) with the component (ii) at 100 to 190 ° C given if carried out in the presence of a catalyst is (see DE-OS-35 18 770).

Further particularly preferred (α) components are Ver bonds that can be produced by a 100 to 195 ° C, optionally in the presence of a cata- performed by a monofunctional reaction starter who is either an alcoholic OH group pe, a phenolic OH group or an SH group carries initiated polyaddition of a diepoxide compound and / or a mixture of diepoxide compounds, optionally together with at least one mono epoxy compound, to an epoxy resin in which diepoxide compound and starter in a molar ratio of greater than 2: 1 to 10: 1 are installed (see. DE-OS 35 18 732).

Polyepoxides, which are especially suitable for the production of zugten (α) components and also as (α) -Kompo can be used are polyphenols and Epi Halohydrinen produced polyglycidyl ethers of poly phenols. As polyphenols z. B. very special preferably bisphenol A and bisphenol F used become. In addition, 4,4'-dihydroxybenzophenone, Bis (4-hydroxyphenyl) 1,1-ethane, bis (4-hydroxyphe nyl) -1,1-isobutane, bis (4-hydroxy-tertiary-butylphe  nyl) -2,2-propane, bis- (2-hydroxynaphthyl) -methane, 1,5-dihydroxynaphthalene and phenolic novolac resins suitable.

Other suitable polyepoxides are polyglycidyl ethers of polyhydric alcohols, such as. For example, ethylene glycol, Diethylene glycol, triethylene glycol, 1,2-propylene glycol, 1,4-propylene glycol, 1,5-pentanediol, 1,2,6-hexanetriol, Glycerol and bis- (4-hydroxycyclohexyl) -2,2-propane. It may also polyglycidyl esters of polycarboxylic acids, such as z. As oxalic acid, succinic acid, glutaric acid, Tereph thalian acid, 2,6-naphthalenedicarboxylic acid and dimerized Linoleic acid are used. Typical examples are Glycidyl adipate and glycidyl phthalate.

Further, hydantoin epoxides, epoxidized polybutadiene and polyepoxide compounds which are passed through Epoxidation of an olefinically unsaturated aliphati receives a connection.

Among modified polyepoxides are polyepoxides understood, in which at least part of the reaction enabled groups with a modifying connection have been implemented.

As examples of modifying compounds called:

• - Carboxyl-containing compounds, such as saturated or unsaturated monocarboxylic acids (eg benzoin acid, linseed oil fatty acid, 2-ethylhexanoic acid, Versa tic acid), aliphatic, cycloaliphatic and / or aromatic dicarboxylic acids of various chains length (eg adipic acid, sebacic acid, isophthalic acid acid or dimer fatty acids), hydroxyalkylcarbon  acids (eg lactic acid, dimethylolpropionic acid) and carboxyl-containing polyesters or
• - amino-containing compounds, such as diethylamine or ethylhexylamine or diamines with secondary Amino groups, e.g. N, N'-dialkylalkylenediamines, such as Dimethylethylenediamine, N, N'-dialkyl-polyoxyalkylene amines, such as N, N'-dimethylpolyoxypropylenediamine, cyanoalkylated alkylenediamines, such as bis-N, N'-cyano ethyl-ethylenediamine, cyanoalkylated polyoxyalkylene amines, such as bis-N, N'-cyanoethylpolyoxypropylenediamine, Polyaminoamides, such as. B. versamides, in particular terminal amino-containing reaction pro diamines (eg hexamethylenediamine), poly carboxylic acids, especially dimer fatty acids and Monocarboxylic acids, especially fatty acids or the Reaction product of one mole of diaminohexane with two moles of monoglycidyl ether or monoglycidyl ester, especially glycidyl ester α-branched fat acids, such as Versatic acid, or
• hydroxyl-containing compounds, such as neopentyl glycol, bisethoxylated neopentyl glycol, hydroxy pivalic acid neopentyl glycol ester, dimethylhydane toin-N, N'-diethanol, hexanediol-1,6, hexanediol-2,5, 1,4-bis (hydroxy-methyl) cyclohexane, 1,1-isopropyli den-bis (p-phenoxy) -2-propanol, trimethylolpropane, Pentaerythritol or amino alcohols, such as triethanol amine, methyldiethanolamine or hydroxylgruppenhal alkylketimines, such as aminomethylpropanediol-1,3- methyl isobutyl ketimine or tris (hydroxymethyl) aminomethancyclohexanonketimine as well as polyglyne colethers, polyester polyols, polyether polyols, poly caprolactone polyols, polycaprolactam polyols ver different functionality and molecular weights or  
• saturated or unsaturated fatty acid methyl esters, in the presence of sodium methylate with hydroxyl groups of epoxy resins are transesterified.

As component (β) may be primary and / or secondary Amines are used.

Preferably, the amine should be a water-soluble Ver be binding. Examples of such amines are mono- and Dialkylamines, such as methylamine, ethylamine, propylamine, Butylamine, dimethylamine, diethylamine, dipropylamine, Methylbutylamine and the like. Also suitable are Alka nolamine, such as. As methyl ethanolamine, diethanolamine and Like. Further Dialkylaminoalkylamine, such as. B. Dimethylaminoethylamine, diethylaminopropylamine, di methylaminopropylamine and the like. Suitable. It can too ketimine-containing amines, such as. As the Methylisobu tyldiketimin be used by diethylenetriamine. In In most cases, low molecular weight amines ver but it is also possible to use higher molecular weight mono amine.

The amines may also contain other groups, but these are the implementation of the amine with the Do not disturb epoxy group and not to one Gelation of the reaction mixture lead.

Preference is given to secondary amines as (β) component used.

The water dilutability and electrical Ab necessary charges can be made by Proto with water-soluble acids (eg boric acid, Formic acid, lactic acid, preferably acetic acid) become. Another way to introduce  cationic groups consists in the implementation of Epoxide groups of component (α) with amine salts.

The ent in the electrodeposition paints according to the invention cathodically depositable synthetic resins are in the Usually either self-crosslinking and / or come with a crosslinking agent or a mixture of Ver networking agents combined.

Self-crosslinking resins are available by adding the synthetic resin molecules introduced reactive groups which are under stoving conditions with each other react. For example, in hydroxyl and / or amino group-containing resins blocked isocyanate be introduced under Einbrennbedingun deblocking and networking Lackfilmen with the hydroxyl or amino groups reactie For example, self-crosslinkable synthetic resins can be used by reaction of a hydroxyl and / or amino groups containing resin with a partially blocked polyiso cyanate, which on a statistical average is a free NCO Group contains per molecule.

The electrodeposition paints of the invention can in Principle all suitable for electrocoating Ver networking means such. B. phenolic, polyfunctional Mannich bases, melamine resins, benzoguanamine resins, blocked polyisocyanates and activated ester groups containing compounds. The erfindungsge The electrocoating paints preferably contain blocked polyisocyanates as crosslinking agents. The Use of blocked polyisocyanates in cathodic starting coatable resins containing electrodeposition paints has long been known and among others in the cited in detail above patent documents ben. Suitable blocked polyisocyanates may be included in  For example, be prepared by the below be written component (a) with the below described Component (d) to an NCO group-free product is set.

It is essential to the invention that the invention Electrodeposition paints contain polymer microparticles which can be produced by

• (a) a polyisocyanate or a mixture of poly with isocyanates
• (b) an organic compound that is so per molecule probably at least one ethylenically unsaturated dop pelbindung as well as at least one active water contains substance atom or a mixture of such organic compounds and
• (c) an organic compound that is so per molecule probably at least one active hydrogen atom as also at least one tertiary amino group and / or at least one ketimine and / or at least one Aldimine group contains or a mixture of sol chen organic compounds and optionally
• (d) one of (b) and (c) different organic Compound containing at least one active molecule per molecule Contains hydrogen atom or a mixture of such organic compounds

is reacted in such a proportion that 3 to 80, preferably 5 to 40 percent of the NCO groups component (a) with component (b), 3 to 80, preferably 3 to 15 percent of the NCO groups of Kom component (a) with the component (c) and 0 to 94, before preferably 45 to 92 percent of the NCO groups of the compo  (a) be reacted with the component (d) and the reaction product thus obtained is dispersed in water gelled and free-radically polymerized, wherein during or after dispersion at least 5 pro cent, preferably at least 10 percent of the Um settlement product contained tertiary and / or primary Amino groups neutralized with a Brönsted acid become.

The reaction of components (a), (b), (c) and give where appropriate (d) can be used both in substance and in orga niche solvents such. As hydrocarbons, such as Toluene or xylene, ketones, such as methyl ethyl ketone or Methyl isobutyl ketone or ethers such as dioxane and ethyl be carried out with glycol dibutyl ether. The Um tion is preferably in organic solvents carried out. The reaction temperature is more usual example 30 to 150, preferably 40 to 100 ° C. The Um can also be catalyzed. As examples of Suitable catalysts will be organic tin compound such as dibutyltin dilaurate and dibutyltin oxide ge Nannt. The reaction is preferably in the presence a polymerization initiator such. B. di-tert-butyl cresol, pentaerythrityl tetrakis [3- (3,5-di-tert-butyl-4-) hydroxyphenyl) propionate] (Irganox 1010 from Ciba Geigy) or p-benzoquinone.

The selection of the quantity ratio in which the compo (a), (b), (c) and optionally (d) with each other have to be implemented so that 3 to 80, preferably 5 to 40 Percent of the NCO groups of component (a) with the Kom component (b), 3 to 80, preferably 3 to 15 percent the NCO groups of component (a) with the component (c) and 0 to 94, preferably 45 to 92 percent of NCO groups of component (a) with component (d) be implemented by the skilled person by stöchi  metric calculations easily possible. In some Cases, it may be advantageous to use the components (a), (b), (c) and, if appropriate, (d) implement in stages.

After reaction of components (a), (b), (c) and gege if appropriate (d) the reaction product obtained is dissolved in Water dispersed and then radically poly merized. In order to obtain a stable aqueous dispersion This is done before, during or after dispersion much of a Brönsted acid or a mixture of Brön sted acids are added to the reaction product that min at least 5 percent, preferably at least 10 percent the tertiary and / or primary amino groups with a Brönsted acid neutrali be siert. The primary amino groups are formed by Hydrolysis of the ketimine and / or aldimine groups. When Brönsted acids can be, for example, acetic acid, Lactic acid, oxalic acid, tartaric acid or mixtures of These Brönsted acids are used.

The reaction product generally contains 0.1 to 2.3, preferably 0.2 to 0.8 mmol / g (based on solid substance) cationic groups in the form of protonated tertiary and / or primary amino groups.

The radical polymerization of the reaction product is done by adding a free radical-forming Polymerization initiator or a mixture of free Radical forming polymerization initiators. Free Radical forming polymerization initiators are Ver bindings, after the supply of energy, for example wise by irradiation or supply of thermal Energy (i.e., by heating), into free radicals fall and the polymerization of the through the component (b) ethylenic introduced into the reaction product initiate unsaturated double bonds. About that  In addition, redox systems can be used. The Time at which the free-radical-forming polymeri sationsinitiator or the mixture of free radicals forming polymerization initiators to the reaction product is to be chosen so that the radi kalische polymerization of the reaction product only after dispersing the reaction product in what takes place. As a free radical forming Polymerisa tion initiators are preferably free radicals forming polymerization initiators used, the by supplying thermal energy into free radii kale crumble. Especially preferred are free radii kale forming polymerization initiators used, which form free radicals from temperatures of 50 ° C.

Free-radical-forming polymerization initiators For example, azo compounds such as Azobisisobutyronitrile, azobisisovaleronitrile, Perver compounds such as dilauroyl peroxide, diacetyl peroxydicarbonate, tert-butyl peroxydiethylacetate and Dibenzoyl peroxide and redox systems, such as Hydrogen peroxide or potassium peroxydisulfate in com combination with iron (II) sulphate and sodium sulphite, be used.

As component (a), in principle, any organic Ver which has a statistical average of at least 1.1 NCO Contains groups per molecule or a mixture of sol chen organic compounds are used. When Component (a) is preferably a polyisocyanate which on average 1.1 to 3.0 NCO groups per Contains molecule or a mixture of such polyiso used cyanates. As component (a), alipha tables, cycloaliphatic or aromatic polyiso cyanates, cyanut produced from these polyisocyanates rat- and / or biuret-containing addition products  and from these polyisocyanates and hydroxyl and / or amino-containing lower or higher molecular weight Ver bonds (for example trimethylolpropane, polyester polyols and polyether polyols) produced NCO groups containing prepolymers are used. As examples for usable polyisocyanates are called: 2,4- and 2, 6-tolylene diisocyanate, isophorone diisocyanate, hexa methylene diisocyanate, 4,4'- and 2,4'-diphenylmethanedi isocyanate. It can also carbodiimid- or uretonimine Group-containing polyisocyanates as component (a) be set.

As component (b), in principle, any organic Ver bond containing at least one ethyle per molecule nisch unsaturated double bond as well as at least contains an active hydrogen atom or a mixture be used from such organic compounds. Under active hydrogen atoms are with NCO groups understood reactive hydrogen atoms. As a component (b) may be, for example, an organic compound be set, which are both an ethylenic molecule per molecule unsaturated double bond as well as a hydroxyl, contains an amino or a mercapto group.

Component (b) used is preferably a derivative of acrylic acid or methacrylic acid which contains a hydroxyl or mercapto group, preferably a hydroxyl group, or a mixture of such derivatives of acrylic acid or methacrylic acid. As Beispie le for usable acrylic or methacrylic acid derivatives are called: 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl acrylate, 2-hydroxypropyl methacrylate, 3-hydroxypropyl acrylate, 3-hydroxypropyl methacrylate, 4-hydroxybutyl acrylate, 4-Hydroxybutylmeth acrylate and their ethoxylated or propoxylated derivatives containing 1-50, preferably 1-8, more preferably 1-3, alkylene oxide units. As component (b) very particular preference is given to using a hydroxyalkyl ester of acrylic acid or methacrylic acid or a mixture of hydroxyalkyl esters of acrylic acid or methacrylic acid. The hydroxyalkyl usually have 1 to 6, preferably 2 to 4 carbon atoms in the alcohol radical. Examples of very particularly preferably used hydroxyalkyl esters are:
2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate,
2-hydroxypropyl acrylate, 2-hydroxypropyl methacrylate,
3-hydroxypropyl acrylate, 3-hydroxypropyl methacrylate,
4-hydroxybutyl acrylate and 4-hydroxybutyl methacrylate.

As component (c), in principle, any organic Ver bond, which has at least one active molecule per molecule Hydrogen atom as well as at least one tertiary one Amino group and / or at least one ketimine and / or contains at least one Aldimingruppe or a Mi used from such organic compounds become. Under active hydrogen atoms are with NCO- Groups of reactive hydrogen atoms understood. The ketimine or aldimine group containing compounds available by making compounds that are both an against via NCO groups active hydrogen atom as well as min at least one primary amino group in the molecule with a ketone, such as As acetone, methyl ethyl ketone or methyl isobutyl ketone or an aldehyde, preferably in an organic solvent such. B. Xylene, toluene or n-hexane, are reacted. The Reaction is usually at elevated temperatures carried out, the reaction water by azeotropic Distillation is removed.

As component (c), for example, an organic Compound used per molecule both  a hydroxyl, an amino or a mercapto group as well as at least one tertiary amino group and / or at least one ketimine and / or at least one Aldimine group contains. There are connections that are pro Molecule of both a hydroxyl, a primary amino or a secondary amino group as well as a tertiary one Contain amino group or a ketimine group before Trains t. As examples of such compounds are named: N, N-dimethylethanolamine, N, N-diethylethanol amine, N, N-butylethylpropanolamine, N, N-dimethylamino ethylamine, N, N-diethylaminoethylamine, N, N-dimethyl aminopropylamine, N, N-diethyl-amino-propylamine, N, N- Dimethylaminoethyl mercaptan, N, N-diethylaminoethylmer captan and reaction products of acetone, methylethyl ketone, methyl isobutyl ketone, dihydroisophorone or iso phoron with β-aminoethanol, β-aminomercaptan, 2,2'- Aminoethoxyethanol, N-aminoethylpiperazine, diethylene triamine, dipropylenetriamine and dibutylenetriamine.

As component (c) are particularly preferably verbin used in the general formula A-R³-X (I), where A is a group of the general formula R¹R²N- or R¹R²C = N-, R³ is an alkylene radical with 1 to 20, preferably 2 to 6, more preferably 2 to 4 C atoms or for a group of the general formula -R⁴-O-R⁵- and X is a hydroxyl group, a primary amino group or a group of general Formula -NH-R⁶, where R¹ and R² are the same or ver can be divided and each for a coal serstoffrest with 1 to 20, preferably 1 to 6, in particular in each case for an alkyl radical having 1 to 6, preferably 1 to 4 carbon atoms, R⁴ and R⁵ are the same or may be different and each for one Alkylene radical having 1 to 12, preferably 1 to 6, in particular ders preferably 1 to 4 carbon atoms and R⁶ is a Hydrocarbon radical having 1 to 20, preferably 1 to  6, particularly preferred for an alkyl radical with 1 to 6, preferably 1 to 4 C atoms or for a group of general formula -R3-A, where A and R3 are the above have meaning explained. As examples of verbin compounds of general formula (I) are named: N, N-dimethylethanolamine, N, N-diethylethanolamine, N, N- Dimethylpropanolamine, N, N-diethylpropanolamine, N, N- Butylethylpropanolamine, N, N-dimethylaminoethylamine, N, N-dimethylaminopropylamine, N, N-diethylaminoethylamine, N, N-diethylaminopropylamine and reaction products Acetone, methyl ethyl ketone, methyl isobutyl ketone, dihydro isophorone or isophorone with β-aminoethanol, 2,2'- Aminoethoxyethanol, N-aminoethylpiperazine, diethylene triamine and dipropylenetriamine.

As component (d), in principle any of (b) and (c) various organic compounds are used the per molecule at least one active hydrogen atom contains or a mixture of such organic Ver be used. As component (d) be preferably well-known blocking agents for poly isocyanates used. Examples are: Aliphatic monoethers of alkanediols, such as ethyl, Propyl and butyl glycol; aliphatic monoalcohols with 1 to 4 C atoms in the molecule, such as methanol, ethanol, Pro panol and butanol; cycloaliphatic monoalcohols, such as cyclohexanol; aromatic alkyl alcohols, such as phenyl carbinol; Phenol compounds, such as phenol itself and substituted phenols, such as cresol, nitrophenol, chlorine phenol and ethylphenol; Amines, such as di-n-butylamine, Di-sec-butylamine, dicyclohexylamine, piperidine, 2-methylpiperidine and 2,6-dimethylpiperidine; Oxime, how Acetone oxime, butanone oxime, diethyl ketoxime, methylethyl ketoxime, methyl isobutyl ketoxime, diisopropyl ketoxime, Cyclohexanone oxime, 2-methylcyclohexanone oxime, 2,6-di methylcyclohexanone oxime, acetophenone oxime; Lactams, like  ε-caprolactam and CH-acidic compounds such as dialkyl malonates, alkylacetoacetates, acetylacetone; hetero cyclic compounds such as furfuryl alcohol, etc. As Component (d) may also include polyols, preferably ali phatic polyols containing 2 to 20, preferably 2 to 10 C atoms and 2 to 5, preferably 2 to 3 Hydroxylgrup pen per molecule, such as. For example, ethylene glycol, Propanediol, butanediol, hexanediol, glycerol, and tri methylolpropane be used. As component (d) can furthermore hydroxyl-containing polyethylene oxides, polypropylene oxides, polytetramethylene oxides and their copolymers are used.

The erfindungsmäßen aqueous electrodeposition paints can in addition to the components described above also more conventional paint components such. B. organic Solvents, pigments, fillers, wetting agents, Antikra teradditive etc. included.

The solids content of the electrocoat according to the invention Lacke is generally 5 to 40, preferably 10 to 40, more preferably 20 to 40 weight percent.

The non-volatile portion of Elek invention dipcoats consists of 35 to 70, preferably 35 to 65 wt .-% of a cathodically depositable resin or a mixture of cathodic depositable art resins to 0 to 45, preferably 10 to 35 wt .-% of one of the polymers used according to the invention microparticles of various crosslinking agents or a mixture of the inventively used Polymer microparticles of various crosslinkers, from 5 to 45, preferably 10 to 20 wt .-% of the Polymer microparticles used according to the invention and from 5 to 35, preferably from 15 to 35,% by weight of pigments th and / or fillers.  

The electrodeposition paints according to the invention are used for Painting electrically conductive substrates used, in which

• (1) the electrically conductive substrate in an aqueous immersed in electrocoating paint,
• (2) the substrate is switched as a cathode,
• (3) a film deposited on the substrate by direct current will be divorced,
• (4) the painted substrate from the electrodeposition paint is removed and
• (5) the deposited paint film is baked.

The above-described method is known and is used for several years on a large scale (See also the patent documents cited above). The applied voltage can be in a wide range can fluctuate and, for example, between 2 and 1000 V lie. Typically, however, with voltages zwi 50 and 500 V worked. The current density is in usually between about 10 and 100 A / m². In the course of Deposition, the current density tends to fall. As soon as the paint film is deposited on the substrate is the painted substrate ent from the electrocoating removed and rinsed off. After that, the secluded Branded paint film. The baking temperatures are usually at 130 to 200 ° C, preferably at 150 to 180 ° C and the burn time is generally between 10 and 60 min., preferably between 15 and 30 min.  

With the method described above, in principle all electrically conductive substrates are painted. As examples of electrically conductive substrates be substrates of metal, such as steel, aluminum, Called copper and the like.

The invention will become more apparent in the following examples explained. All information about parts and percentages are weights, if not expressly other is determined.

1. Preparation of Crosslinking Agents 1.1 Crosslinking Agent I

In a reactor equipped with a stirrer, reflux condenser, Indoor thermometer and inert gas inlet equipped is 1046 g of isomers and higher functional oligo mers based on 4,4'-diphenylmethane diisocyanate with an NCO equivalent weight of 135 (Luprana® M20S, Fa. BASF; NCO functionality approx. 2.7; Content of 2,2'- and 2,4'-diphenylmethane diisocyanate below 5%) Nitrogen atmosphere presented. 2 g of dibutyl are added tin dilaurate and dripping 963 g of butyl diglycol with at such a rate that the product temp temperature remains below 60 ° C. If necessary, must be cooled become. After the addition, the temperature is white Tere 60 min held at 60 ° C and an NCO Equivalentge weight of 1120 (based on fixed shares). To Dissolution in 774 g of methyl isobutyl ketone and addition of 3 g of dibutyltin dilaurate are 87 g of molten tri methylolpropane added at such a rate ben, that a product temperature of 100 ° C does not exceed  is taken. After the end of addition is allowed to a further 60 min afterreact. At the subsequent inspection are no more NCO groups detectable. It is cooled to 65 ° C and diluted simultaneously with 96 g of sec-butanol and 30 g of methyl isobutyl ketone. The solids content is included 70.1% (1 h at 130 ° C).

1.2 Crosslinking Agent II

In a reactor, as in the above example be is written under nitrogen atmosphere 1464 g trimerized hexamethylene diisocyanate with an NCO- Equivalent weight of 191 ("Basonat® PLR 8638", Fa. BASF) and 510 g of methyl isobutyl ketone with stirring Heated to 50 ° C. During 4 h 936 g of di-n-butyl are now amine dripped. The temperature is thereby cooled by Küh kept below 55 ° C. The crosslinker solution is then cooled and with 90 g of n-butanol ver thinned. In the subsequent control, no NCO Groups detectable. The solids content is included 79.8% (measured at 130 ° C for 1 h).

2. Preparation of an aqueous dispersion the one cathodic resin and a mixture from crosslinking agents

In a reactor are based on 1228 parts of epoxy resin of bisphenol A with an epoxy equivalent weight (EEW) of 188 along with 279 parts bisphenol A, 268 parts Dodecylphenol and 89 parts of xylene under nitrogen Atmosphere heated to 105 ° C. With the help of a what serabscheiders be 20 min by azetrope reflux Distilled in vacuo traces of water. It is then heated to 130 ° C and 5 parts N, N  Dimethylbenzylamine too. At this temperature, the Reaction until the EEW has a value of 870 has reached. There are now 39 parts of butyl glycol, 204 parts of sec-butanol and, after cooling below 115 ° C., 139 parts of diethanolamine and further cooled to 90 ° C. from. One hour after addition of amine, 192 parts are used Plastilit 3060 (propylene glycol compound, BASF) too and diluted with 144 parts of sec-butanol and 55 parts Propylene glycol phenyl ether and cools quickly at the same time to 65 ° C. Thereafter, 39 parts of N, N-dimethylamines are added nopropylamine, keeps the temperature for half an hour and then heated to 90 ° C. This temperature is held for 1.5 hours. Then it is lowered to 70 ° C cools. To the reaction mixture are 743 parts Ver networking agent I (item 1.1) and 650 parts of crosslinking added medium II (item 1.2), homogenized for 10 min and transferred to a dispersing vessel. There you give with stirring 107 parts of lactic acid (88% pure in water) in 2203 parts of deionized water. The mixture is then homogenized for 20 minutes before using another 3593 parts of deionized water in small Portions is diluted further.

By distillation in vacuo, the volatile Solvent removed and then by the same amount deionized water replaced. The dispersion has the following key figures:

Solids content: 32% (1 hour at 130 ° C) Base Salary: 0.66 milliequivalents / g of solids Acidity: 0.25 milliequivalents / g of solids pH: 6.1

3. Preparation of a gray pigment paste

2781 parts bisphenol A diglycidyl ether, 144 parts xylene and 581 parts bisphenol-A in the presence of 0.2 Share triphenylphosphine at 150-160 ° C until a EEW of 345 implemented. The approach then becomes 2161 Parts of butyl glycol diluted and cooled to 49 ° C. Then is a mixture of 777 parts of 9-amino-3,6-dioxano nan-1-ol and 407 parts of N, N-dimethylaminopropylamine Add within 6 min, whereupon the temperature rises 110 ° C rises. The mixture is kept for one hour between 110 and 115 ° C before 645 parts butylglycol zugege ben and the batch is cooled to 77 ° C. Subsequently, 149 parts Nonylphenolglycidether added. The temperature then rises to 90 ° C and is held there for an hour before with 1003 Parts of butyl glycol are diluted and cooled. The festival content of the low-viscosity resin solution is 60%.

For the preparation of the pigment paste are initially 280 Parts of water and 250 parts of those described above Resin solution premixed. Now 5 parts of soot, 35 Parts of basic lead pigment, 90 parts Extender HEWP (English China Clay Int., Great Britain), 315 parts titanium dioxide (R 900), 5 parts Bentone EW (Rheox, Germany) and 20 parts dibutyltin oxide added. The mixture will For 30 minutes under a high-speed dissolver stirring factory predispersed. Subsequently, the mixture is in a laboratory mini mill (Motor Mini Mill, Eiger Engineering Ltd., Great Britain) for 1 to 1.5 hours up to a Hegmann fineness of less than or equal to 12 dispersed and with more water on processing adjusted viscosity.

A demixing-stable pigment paste is obtained.  

4. Preparation of aqueous dispersions, the inventions According to the polymer microparticles used according to ent hold 4.1 Preparation of the dispersion I

In a reactor equipped with a stirrer, reflux condenser, Internal thermometer and inert gas line is equipped, 1021 g of toluene diisocyanate (mixture of about 80 % By weight of 2,4 and 20% by weight of 2,6-isomers) and 180 g of methyl isobutyl ketone under nitrogen atmosphere. you adds 0.4 g of dibutyltin dilaurate and carries within one hour heated to 70 ° C solution of 254 g of trimethylolpropane in 254 g of methyl isobutyl ketone on. The cooling is regulated so that the temperature Does not exceed 60 ° C.

30 minutes after the addition, an NCO equivalent weight measured from 217, based on solids. Under wide Cooling is allowed within 20 min 102 g of n-Pro plyglycol dripping, with the temperature rise to 55 ° C is limited. Subsequently, the Reaktionsge cooled to 40 ° C mixed. Become the reactor contents 564 g of hydroxypropyl methacrylate, in which previously 0.4 g of di- tert-butyl-p-cresol were dissolved, added dropwise. The Speed of addition is controlled so that the Temperature of the reaction mixture 50 ° C not exceeded tet. After the end of the addition (about one hour) the Batch maintained at 50 ° C and an NCO equivalent weight of 1670, based on solids content determined. To simultaneous addition of 433 g of methyl isobutyl ketone and Cooling to 35 ° C to the reaction mixture 115 g N, N-diethylethanolamine added in one portion. To 30 min further 0.6 g of di-tert-butyl-p-cresol in 20 g sec-butanol added. As soon as no NCO groups  can be detected more, you put the reaction tion mixture with 16 g azobisisovaleronitrile, which previously dissolved in 39 g of methyl isobutyl ketone. 1309 Parts of the organic solution thus obtained are in a dispersing vessel with 492 parts of deionized What containing 35 parts of lactic acid (88% in water) stops, staggered. It is then homogenized for 20 minutes siert, with another 995 parts of deionized water diluted with stirring, heated to 70 ° C and 10 hours stirred at this temperature for a long time. The thus obtained Dispersion has a solids content of 32.2% (1 h, 130 ° C).

4.2 Dispersion II 4.2.1 Preparation of an organic compound which both an active hydrogen atom per molecule and a ketimine group

In a reactor equipped with stirrer, inert gas line, water separator and reflux condenser 1100 g of 2,2'-aminoethoxyethanol (H₂N-CH₂CH₂-O-CH₂CH₂- OH) and 1886 g of methyl isobutyl ketone and presented in a nitrogen atmosphere with stirring slowly heated. From 109 ° C condensation water is separated. One raises the temperature in small steps in within 3 h up to 142 ° C and stops at this Temperature, until 189 g of water are removed. to closing is cooled to 40 ° C and under nitrogen discharged.

The cooled solution has an amine equivalent weight from 265 on.  

4.2.2 Preparation of the dispersion II

In a reactor equipped with a stirrer, refluxing ler, internal thermometer and inert gas line is 992 g of toluene diisocyanate (mixture of about 80% by weight of 2.4 and 20% by weight of 2,6 isomers) and 175 g Methyl isobutyl ketone under nitrogen atmosphere sets. Add 0.4 g of dibutyltin dilaurate and carry tempered to 70 ° C within 1 hour Solution of 247 g of trimethylolpropane in 247 g of methyl iso butyl ketone. The cooling is regulated so that the Temperature does not exceed 60 ° C.

30 minutes after the end of the addition, an NCO equivalent weight is obtained of 208 measured (based on solids). Under Further cooling is allowed within 20 min 119 g Add dropwise n-propyl glycol, with the temperature rise is limited to 55 ° C. Subsequently, the Reak tion mixture cooled to 40 ° C. To the reactor contents 548 g of hydroxypropyl methacrylate, in the previously 0.4 g of di-tert-butyl-p-cresol were dissolved, added dropwise. The rate of addition is controlled so that the temperature of the reaction mixture does not exceed 50 ° C below. After the end of the addition (about 1 h) is the Approach kept at 50 ° C and an NCO Equiva lentgewicht von 2015, based on fixed portion, be Right. After simultaneous addition of 420 g of methyl isobutyl ketone and cooling to 35 ° C become a reac 178 g of the mixture described in point 4.2.1 Reaction product of 2,2'-aminoethoxyethanol and Methyl isobutyl ketone added in one portion. To 30 min further 0.6 g of di-tert-butyl-p-cresol in 19 g sec-butanol added. As soon as no NCO groups can be detected more, you put that Reaction mixture with 16 g of azobisisobutyronitrile,  which was previously dissolved in 38 g of methyl isobutyl ketone has been. 2142 parts of the organic solution thus obtained are in a dispersion vessel with 1718 parts de ionized water containing 57 parts of lactic acid (88% in Water), offset. Then 25 Tei Butyl glycol added and homogeneous for 20 min Siert. The mixture is mixed with another 3488 parts deionized water with stirring, further diluted Heated to 70 ° C and for 10 hours at this temperature touched. The dispersion thus obtained has a Solids content of 20.4% (1 h, 130 ° C).

5. Preparation and deposition of inventive Elek trotauchlacke 5.1 Electrocoating paint (I)

2078 parts of the dispersion according to item 2 and 516 parts the dispersion according to point 4.1 are mixed and mixed with 1500 parts of deionized water and 25 parts of a Diluted 10% aqueous solution of lactic acid. To the so The resulting mixture is 646 parts of the pigment paste added according to point 3 with stirring. The thus obtained Electrodeposition paint becomes with deionized water to 5000 Parts filled up. After 5 days of aging at room temp The temperature is measured on a cathodically connected steel test isolated. In this case, the deposition voltage is 300 V, the deposition time 2 min and the bath temperature is set to 30 ° C. The deposited paint film is rinsed with deionized water and for 20 min baked at 165 ° C. The so obtained branded Paint films were tested. The test results can be the Table 1 are taken.  

5.2 Electrocoating paint (II)

2078 parts of the dispersion according to point 2. and 815 parts the dispersion according to point 4.2 are mixed with and 1300 parts of deionized water and 25 parts of a Diluted 10% aqueous solution of lactic acid. To the so The resulting mixture is 646 parts of the pigment paste added according to point 3 with stirring. The thus obtained Electrodeposition paint becomes with deionized water to 5000 Parts filled up. After 5 days of aging at room temp The temperature is measured on a cathodically connected steel test isolated. In this case, the deposition voltage is 300 V, the deposition time 2 min and the bath temperature is set to 30 ° C. The deposited paint film is rinsed with deionized water and for 20 min baked at 165 ° C. The so obtained branded Paint films were tested. The test results can be the Table 1 are taken.

6. Preparation and deposition of an electrodeposition paint the prior art (electrodeposition paint (III); Comparative example

2598 parts of the dispersion according to point 2. are with 1500 parts of deionized water and 25 parts of a Diluted 10% aqueous solution of lactic acid. To the so The resulting mixture is 646 parts of the pigment paste added according to point 3 with stirring. The thus obtained Electrodeposition paint becomes with deionized water to 5000 Parts filled up. After 5 days of aging at room temp The temperature is measured on a cathodically connected steel test isolated. In this case, the deposition voltage is 300 V, the deposition time 2 min and the bath temperature is set to 30 ° C. The deposited paint film  is rinsed with deionized water and for 20 min baked at 165 ° C. The so obtained branded Paint films were tested. The test results can be the Table 1 are taken.

Table 1

Claims (8)

1. Cathodic electrodepositable resins containing aqueous electrical dipcoats, characterized in that they contain polymer microparticles having a particle size of 0.01 to 10 microns, which are produced by

• (a) a polyisocyanate or a mixture of polyisocyanates with
• (B) an organic compound containing per molecule both at least one ethylenically unsaturated double bond and at least one active hydrogen atom or a mixture of such organic compounds and
• (C) an organic compound containing per molecule both at least one active hydrogen atom and at least one tertiary amino group and / or at least one ketimine and / or at least one aldimine or a mixture of such organic connec tions and optionally
• (d) an organic compound other than (b) and (c) which contains at least one active hydrogen atom per molecule or which is reacted with a mixture of such organic compounds in such a proportion that 3 to 80 percent of the NCO groups of the component (a) with component (b), 3 to 80 percent of the NCO groups of component (a) with component (c) and 0 to 94 percent of the NCO groups of component (a) with component (d) be reacted, the resulting reaction product per giert in water and polymerized free-radically, wherein before, during or after the dispersion of at least 5 percent of ter contained in the reaction product ter and / or primary amino groups are neutralized with a Brönsted acid.

2. Electrodeposition paints according to claim 1, characterized marked characterized in that as component (a) a polyisocyanate, the statistical average of 1.1 to 3.0 NCO groups contains per molecule or a mixture of such Polyisocyanates is used. 3. Electrodeposition paints according to claim 1 or 2, characterized characterized in that as component (b) is a derivative of acrylic acid or methacrylic acid, which is a Hy hydroxyl, an amino or a mercapto group ent holds or a mixture of such derivatives of Acrylic acid or methacrylic acid is used. 4. Electrocoating paints according to one of claims 1 to 3, characterized in that as component (b) a Hydroxyalkyl esters of acrylic acid or methacrylic acid or a mixture of hydroxyalkyl esters the acrylic acid or methacrylic acid is used. 5. Electrocoating paints according to one of claims 1 to 4, characterized in that as component (c) a Compound of general formula A-R³-X (I) or a mixture of such compounds used where A is a group of general For mel R¹R²N- or R¹R² C = N-, R³ is a Alkylene radical having 1 to 20 carbon atoms or for a Group of the general formula -R⁴-O-R⁵- is and X for a hydroxyl group, a primary amino group or a group of the general formula -NH-R⁶  wherein R¹ and R² are the same or different can and in each case for a hydrocarbon radical with 1 to 20 carbon atoms, R⁴ and R⁵ are the same or may be different and each for an alky lenrest having 1 to 12 carbon atoms and R⁶ is a hydrocarbon radical having 1 to 20 carbon atoms or for a group of the general formula -R3-A wherein A and R³ have the meaning explained above to have. 6. Electrocoating paints according to one of claims 1 to 5, characterized in that the components (a), (b), (c) and (d) in such a proportion be implemented with each other that 5 to 40 percent the NCO groups of components (a) with the compo (b) 3 to 15 percent of NCO groups Component (a) with component (c) and 45 to 92 Percent of the NCO groups of component (a) with the Component (d) are implemented. 7. A method for painting electrically conductive sub strate, wherein

• (1) immersing the electrically conductive substrate in an aqueous electrodeposition paint,
• (2) the substrate is switched as a cathode,
• (3) a film is deposited on the substrate by direct current,
• (4) the varnished substrate is removed from the electro-dip varnish and
• (5) the deposited paint film is baked,

characterized in that in step (1) of the Ver driving an electrodeposition paint according to one of the Proverbs 1 to 6 is used.